In Vallant’s own words, the #1 most important finding from the Grant Study is this: “The seventy-five years and twenty million dollars expended on the Grant Study points to a straightforward five-word conclusion: Happiness is love. Full stop.”

“Men who had ‘warm’ childhood relationships with their mothers took home $87,000 more per year than men whose mothers were uncaring. Men who had poor childhood relationships with their mothers were much more likely to develop dementia when old. Late in their professional lives, the men’s boyhood relationships with their mothers — but not their fathers — were associated with effectiveness at work. On the other hand, warm childhood relations with fathers correlated with lower rates of adult anxiety, greater enjoyment on vacations, and increased ‘life satisfaction’ at age 75 — whereas the warmth of childhood relationships with mothers had no significant bearing on life satisfaction at 75.”

There's a correlation between warmth of relationships and health / success:

In Triumphs of Experience, Vaillant raises a number of factors more often than others, but the one he refers to most often is the powerful correlation between the warmth of your relationships and your health and happiness in your later years. In 2009, Vaillant’s insistance on the importance of this part of the data was challenged, so Vaillant returned to the data to be sure the finding merited such important focus. Not only did Vaillant discover that his focus on warm relationships was warranted, he placed even more importance on this factor than he had previously. Vallant notes that the 58 men who scored highest on the measurements of “warm relationships” (WR) earned an average of $141,000 a year more during their peak salaries (between ages 55-60) than the 31 men who scored the lowest in WR. The high WR scorers were also 3-times more likely to have professional success worthy of inclusion in Who’s Who.

Yeah, there can be bias, you are right. One other way to think of that is: all of them were ment to make money (because all were Harvard) and some made more than others, experienced more happiness than others, were healthier than others. So, the circumstances why that happened is what matters, right?

Self reported studies are dubious. Self report studies for samples that are already biased are worse.

The data I would like to see is does the other half of warm relationship agree. :-) this demographic is tough and as it ages I bet self reflection actually becomes more difficult. Nobody would believe a study conducted on eulogies.